Idk if it is a bug or glitch but sometimes they just stay on the ground flapping so I trap it with 4 dino gates to kill it and obtain its altar quickly. Then place altar down followed by surround with 8 foundations and 20 tall doors and 9 ceilings. I toss in a thlya set to aggressive to get its aggro to stay in the trap while shooting it or my tribemates helped used their lightning wyverns. One of Loki’s children 💕. Did not realize how huge these are.